This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Until the regeneration of neural tissues is successfully achieved, the prevention of spinal cord injury (SCI) is paramount in mitigating its sequelae. Currently, over 250,000 Americans with SCI must endure its debilitating consequences with little hope of improvement through existing medical treatment. While promising research efforts toward neuro-regeneration and repair are underway, injury prevention offers a means of avoiding SCI which will always be preferable to treatment. One of the keys to preventing SCI is in understanding the limits of human tolerance (i.e., exposure limits) to potential injurious forces acting on the spine. Prevention strategies and devices depend on this knowledge in order to develop effective designs and bench test their performance. Previous injury research has provided exposure limits based on structural failure of the spinal column, but these limits do not provide an indication of the whether the neurologic tissues have been damaged. Because SCI may occur without structural failure of the spine, this study seeks to investigate the threshold (onset) of neurological injury to help determine more conservative exposure limits.